Sesquiterpenes inhibiting NO production from Celastrus orbiculatus

Two new (1 and 2) and one known (3) β-dihydroagarofuran sesquiterpenes were isolated from the fruits of Celastrus orbicultus Thunb. Their structures were elucidated as 1β,13-diacetoxy-8β,9β-dibenzoyloxy-β-dihydroagarofuran (1), 1β,13-diacetoxy-8α-hydroxy-9β-benzoyloxy-β-dihydroagarofuran (2), and 1β,6α,13-triacetoxy-9α-benzoyloxy-β-dihydroagarofuran (3), on the basis of spectroscopic data analyses. All the compounds exhibited inhibitory effects on LPS-induced nitric oxide production in murine microglial BV-2 cells.     

Homoisoflavanones from Ledebouria floribunda

The bulbs of Ledebouria floribunda (Baker) Jessop have yielded two novel compounds, 7-O-[α-rhamnopyranosyl-(1→6)-β-glucopiranosyl]-5-hydroxy-3-(4-methoxybenzyl)-chroman-4-one (1) and 7-O-[α-rhamnopyranosyl-(1→6)-β-glucopiranosyl]-5-hydroxy-3-(4′-hydroxybenzyl)-chroman-4-one (2) along with five other known compounds, 5,7-dihydroxy-3-(4′-methoxybenzyl)-chroman-4-one or 3,9-dihidroeucomin (3), 5,7-dihidroxy-6-methoxy-3-(4′-methoxybenzyl)-chroman-4-one (4), 5,7-dihidroxy 3-(4′-hydroxybenzyl)-chroman-4-one or 4,4′-demethyl-3,9-dihydropuctatin (5), 5,7-dihidroxy-3-(4′-hydroxybenzyl)-6-methoxy-chroman-4-one or 3,9-dihydroeucomnalin (6) and 7-hydroxy-3-(4′-hydroxybenzyl)-5-methoxy-chroman-4-one (7). Their structures were elucidated by spectra analysis. The seven homoisoflavanones were found to be antioxidant against DPPH radical and β-carotene/linoleic acid system.     

New flavonol glycosides from Aconitum burnatii Gáyer and Aconitum variegatum L.

Six flavonol glycosides, compounds 1-3 from A. burnatii Gáyer and 4-6 from A. variegatum L., were obtained from their methanol extracts of aerial parts. The identified structures were quercetin 3-O-β-d-glucopyranoside-7-O-(6-E-p-coumaroyl)-β-d-glucopyranosyl-(1 → 3)-α-l-rhamnopyranoside (1), quercetin 3-O-β-d-glucopyranoside-7-O-β-d-glucopyranosyl-(1 → 3)-α-l-rhamnopyranoside (2), quercetin 3-O-β-d-glucopyranoside-7-O-(6-E-caffeoyl)-β-d-glucopyranosyl-(1 → 3)-α-l-rhamnopyranoside (3), kaempferol 3-O-β-d-galactopyranoside-7-O-α-l-arabinopyranoside (4), quercetin 3-O-β-d-glucopyranoside (5), and kaempferol 3-O-β-d-glucopyranoside (6). Compounds 1, 2 and 4 were isolated for the first time. The antioxidant potential of the methanol extracts and pure compounds was tested with different assays.     

Antibacterial triterpenes from the threatened wood-decay fungus Fomitopsis rosea

From a biologically active extract from the fungus Fomitopsis rosea, two new lanostane triterpenes were isolated, 3α-(3′-butylcarboxyacetoxy)oxepanoquercinic acid C 1 and 3α-hydroxy-24-methylene-23-oxolanost-8-en-26-carboxylic acid 2, along with three known triterpenes, 3–5, and the epidioxy sterol derivative 6. The structures of the compounds were elucidated based on their spectral properties. All triterpenes demonstrated antibacterial activity against S. aureus but possessed no antiradical activity against DPPH radicals.     

Three new sesquiterpenes from Tithonia diversifolia and their anti-hyperglycemic activity

Three new germacrane sesquiterpenes (1), (2), (3), along with eleven known sesquiterpenes, namely, tirotundin-3-O-methyl ether (4), deacetylvguiestin (5), 1β-hydroxydiversifolin-3-O-methyl ether (6), tagitinin C (7), 1β-hydroxytirotundin-3-O-methyl ether (8), 1β-hydroxytirotundin-1,3-O-dimethyl ether (9), tagitinin F-3-O-methyl ether (10), tagitinin F (11), tagitinin A (12), 3β-acetoxy-4α-hydroxyeduesm-11(13)-en-12-oic acid (13) and ilicic acid (14) were isolated from the aerial parts of Tithonia diversifolia. Their structures were established by spectroscopic analysis, while the relative configuration of compound 1 was confirmed by X-ray diffraction analysis. In addition, compounds 1–14 were evaluated in vitro for their anti-hyperglycemic activity by glucose uptake in 3T3-L1 adipocytes. It was found that 10 μg/mL 1, 3, 6 and 8 could significantly increase glucose uptake without significant toxic effects.     

New triterpenoid saponins from Leontice smirnowii

Three new triterpene saponins, leonticins I (1), J (2) and L (3) were isolated from the tubers of Leontice smirnowii. On the basis of spectroscopic methods, including 2D NMR experiments (DEPT, gs-COSY, gs-HMQC, gs-HMBC and gs-HSQC-TOCSY), mass spectrometry (HR-ESI-MS) and chemical degradation, the structures of the new compounds were elucidated as 3-O-β-D-glucopyranosyl-(1 → 3)-[β-D-xylopyranosyl-1 → 2)]-α-L-arabinopyranosyl-28-O-[α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranosyl]-3β-hydroxy-30-norolean-12,20(29)-dien-28-oic acid (1), 3-O-[β-D-xylopyranosyl-(1 → 3)-β-D-galactopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 3)-α-L-arabinopyranosyl]-28-O-[α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranosyl]-3β-hydroxy-30-norolean-12,20(29)-dien-28-oic acid (2) and 3-O-[β-D-xylopyranosyl-(1 → 3)-β-D-galactopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 3)]-[β-D-xylopyranosyl-(1 → 2)]-α-L-arabinopyranosyl]-28-O-[α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranosyl]-3β-hydroxy-30-norolean-12,20(29)-dien-28-oic acid (3), respectively. The aglycone 3β-hydroxy-30-norolean-12,20(29)-dien-28-oic acid was observed for the first time in Leontice species.     

New anthraquinone glycosides from the roots of Morinda citrifolia

Six new anthraquinone glycosides: digiferruginol-1-methylether-11-O-β-gentiobioside (1); digiferruginol-11-O-β-primeveroside (2); damnacanthol-11-O-β-primeveroside (3); 1-methoxy-2-primeverosyloxymethyl-anthraquinone-3-olate (4); 1-hydroxy-2-primeverosyloxymethyl-anthraquinone-3-olate (5); and 1-hydroxy-5,6-dimethoxy-2-methyl-7-primeverosyloxyanthraquinone (6) were isolated from Morinda citrifolia (Rubiaceae) roots together with four known anthraquinone glycosides. The structures of the new compounds were established using spectral methods. For five of the new compounds, the sugar is attached via the hydroxymethyl group of the anthraquinone C-2 carbon. This type of bond is rarely found for anthraquinone glycosides isolated from natural sources.     

A new dilactone from the seeds of Gaultheria yunnanensis

Gaultheriadiolide (1), a new compound, together with the known dauosterol (2), ginkgetin (3), myricetin (4), 6-ethyl-5-hydroxy-2,7-dimethoxy-1,4-naphthoquinone (5), ursolic acid (6), methyl salicylate 2-O-β-d-xylosyl(1→6)β-d-glucopyranoside (7), and methyl salicylate 2-O-β-d-glucopyranoside (8) were isolated from Gaultheria yunnanensis. The structure was elucidated on the basic of spectral analysis, especially 1D and 2D NMR. Primary bioassays showed that compound 1 had medium cytotoxic activity against HEp-2 and HepG2 Cells, with IC₅₀ of 23.337 μM and 29.4497 μM, respectively.     

Two new triterpene saponins from the aerial parts of Paraquilegia microphylla

Two new triterpene saponins, paraquinosides A (1) and B (2) were isolated from the aerial parts of Paraquilegia microphylla (Royle) Dromm. et Hutch, a Tibetan ethnic medicine distributed in the Qinghai–Tibet Plateau. On the basis of 1D and 2D NMR evidence, their structure was elucidated as 3-O-α-L-rhamnopyranosyl (1→2)-β-D-glucopyranosyl-15-dehydroxyl-16-O-methyl-24, 25-deoxy-26-hydroxylshengmanol-26-O-β-D-glucopyranoside (1) and 3-O-α-L-Rhamnopyranosyl (1→2)-[β-D-glucopyranosyl(1→3)]-β-D-glucopyranosyl-15-dehydroxyl-16-O-methyl-24, 25-deoxy-26-hydroxylshengmanol-26-O-β-D- glucopyranoside (2), respectively.     

Dammarane-type glycosides and long chain sesquiterpene glycosides from Gynostemma yixingense

A new dammarane-type glycoside and a new long chain sesquiterpene glycoside, along with nine known compounds 20(S)-ginsenoside Rh1 (3), 20(R)-ginsenoside Rh1 (4), ginsenoside F1 (5), amarantholidoside IV (6), ginsenoside Rc (7), 20(S)-ginsenoside Rg2 (8), 20(R)-ginsenoside Rg2 (9), ginsenoside Rd (10) and gypenoside XLVI (11) were isolated from Gynostemma yixingense. The structures of the new compounds were determined on the basis of spectroscopic analysis, including 1D-, 2D-NMR and ESI-MS techniques as well as by comparison of the spectral data with those of related compounds as 2α,3β,20(S)-trihydroxydammar-24-ene-3-O-[β-d-glucopyranosyl((1 → 2)-β-d-glucopyranosyl]-20-O-[β-d-xylopyranosyl((1 → 6)-β-d-glucopyranoside] (1) (2E,6E)-10-β-d-glucopyranosyl-1,10,11-trihydroxy-3,7,11-trimethyldodeca-2,6-diene (2).     

Isolation and structural characterization of glycosides from an anti-angiogenic extract of Monnina obtusifolia H.B.K.

Angiogenesis, the growth of new blood vessels from the pre-existing vasculature is of physiological and pathological importance. Substantial data over the last decade has implicated uncontrolled angiogenesis with various pathological states. Vascular endothelial growth factors (VEGFs) play a critical role in its regulation, and have become one of the most interesting anti-angiogenesis targets. We have investigated the anti-angiogenic potential of plant extracts in a preliminary ELISA screening. The n-BuOH extract obtained from the leaves of Monnina obtusifolia (Polygalaceae) demonstrated an inhibition of VEGF-A or Placental Growth Factor interaction with Flt-1 (VEGF receptor 1), with an inhibition over 50% in particular for VEGF-A/Flt-1 interaction at a concentration of 500 μg/mL. Successively fractionation of the bioactive n-BuOH extracts of M. obtusifolia aerial parts led to the isolation of six new compounds, 1-O-(4-hydroxy-2-methylene-butanoic acid)-6-O-β-d-(4-hydroxy-2-methylene-butanoyl)-glucopyranose (1), 1-O-(isopentenyl)-6-O-β-d-(4-hydroxy-2-methylene-butanoyl)-glucopyranose (2), 1-O-(4-hydroxy-2-methylene-butanoic acid)-6-O-β-d-(isovaleroyl)-glucopyranose (3), 1-O-(3-methylbut-3enyl)-6-O-β-d-(isovaleroyl)-glucopyranose (4), two new sucrose esters, 3,4-O-β-d-di-feruloyl-fructofuranosyl-6-O-α-d-(p-coumaroyl)-glucopyranoside (5), and 3,4-O-β-d-di-feruloyl-fructofuranosyl-6-O-α-d-(caffeoyl)-glucopyranoside (6), together with known flavonoids. Their structures were established on the basis of detailed spectral analysis. Since none of the isolated compounds showed a relevant inhibition of VEGFs, the biological activity observed for the butanolic extract might be due to the presence of a combination of compounds acting synergistically.     

Three drimane sesquiterpene glucoside from the aerial parts of Dryopteris fragrans (L.) schot

Sesquiterpene glucoside was isolated from the aqueous extract of the aerial parts of Dryopteris fragrans (L.) schot. Three new sesquiterpene glucoside xianglinmaojuesides A–C (1–3), 3β,11-dihydroxy-drim-8 (12)-en-11-O-β-d-glucopyranoside (1), 3β,11-dihydroxy-drim-8(12)-en-3-O-β-d-glucopyranoside (2), and 11,14-dihydroxy-drim-8(12)-en-11-O-β-d-glucopyranoside (3) were finally obtained by reversed-phase HPLC and their structures were elucidated by HRESIMS and 1D, 2D NMR analyses.     

Antioxidant flavonoid glycosides from Evolvulus alsinoides

Oxidative damage is an established outcome of chronic stress. Thus, the present study was designed to investigate the modulatory role of ethanolic extract of Evolvulus alsinoides (EA) in terms of oxidative alterations at peripheral and central level in rats subjected to chronic unpredictable stress (CUS). CUS exposure for 7 days reduced Cu, Zn superoxide dismutase and catalase activity with increase in glutathione peroxidase activity and lipid peroxidation, while decrease in reduced glutathione level in blood plasma, frontal cortex and hippocampus regions of brain. Oral administration of EA extract at 200 mg/kg p.o. normalized these stress induced oxidative alterations with an efficacy similar to that of melatonin. Further, EA extract was taken up for detailed chemical investigation. Two new flavonol-4′-glycoside, kaempferol 4′-O-β-d-glucopyranosyl-(1 → 2)-β-d-glucopyranoside (3) and kaempferol 4′-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside (5) were isolated, along with eight known compounds (1, 2, 4 and 6–10). The structures of new compounds were established by detailed spectroscopic studies, while known compounds were characterized by direct comparison of their reported NMR data. All these compounds were evaluated for their in vitro antioxidant activity. Compounds 3, 5, 9 and 10 at 100 and 200 μg/ml showed significant in vitro antioxidant activity. Therefore, EA may hold great potential in preventing clinical deterioration in stress induced oxidative load and related disorders.     

Sesquiterpenoids from Carpesium divaricatum and their cytotoxic activity

In the course of searching for cytotoxic terpenoids from medicinal plants in China, two new eudesmane sesquiterpenoids, 5α-hydroxy-13-methoxy-7αH,11αH-eudesm-4(15)-en-12,8β-lactone (1) and 1β-hydroxy-7αH,11αH-eudesm-4(15)-en-12,8β-lactone (2), along with fourteen known sesquiterpenoids were isolated from the whole plant of Carpesium divaricatum. The structures of new compounds were determined using spectroscopic methods, including IR, HRESIMS, and 1D and 2D NMR spectroscopy. The cytotoxicity of selected sesquiterpene lactones against human oral epidermoid carcinoma (KB), human breast cancer (MCF-7) and human hepatoma (HepG-2) cells was also evaluated by MTT method.     

A new natural azulene-type pigment from Oreocnide frutescens

A new natural red-purple azulene-type pigment, 1,1,6-trimethylazuleno[1,8-cd]pyran-3(1H)-one, named oreolactone (1), together with nine known compounds, scopoletin (2), pomolic acid (3), friedelin (4), 3β-friedelinol (5), 3α-friedelinol (6), stigmast-4-en-3-one (7), stigmast-4, 22-dien-3-one (8), β-sitosterol (9), and daucosterol (10), was isolated from the rhizomes of Oreocnide frutescens. The structures were elucidated on the basis of spectroscopic analysis.     

Study on secondary metabolite content of Helleborus niger L. leaves

Phytochemical investigation of Helleborus niger L. (Ranunculaceae) leaf methanol extract allowed to isolate a phenolic glucoside derivative and two flavonoid glycosides characterized as phenyllactic acid 2-O-β-d-glucopyranoside (1), quercetin 3-O-2-(E-caffeoyl)-α-l-arabinopyranosyl-(1 → 2)-β-d-glucopyranoside-7-O-β-d-glucopyranoside (2), and kaempferol 3-O-α-l-arabinopyranosyl-(1 → 2)-β-d-galactopyranoside-7-O-β-d-glucopyranoside (3), respectively. Compounds 1 and 2 were isolated for the first time and their structural characterization was obtained on the basis of extensive NMR spectral studies.     

Three new germacrane-type sesquiterpene stereoisomers from the flowers of Chrysanthemum indicum

From the flowers of Chrysanthemum indicum, three new germacrane-type sesquiterpene stereoisomers (1β,3α,5β-trihydroxyl-7-isopropenyl-germacren-4(15), 10(14)-diene (1), 1β,3β,5α-trihydroxyl-7-isopropenyl-germacren-4(15), 10(14)-diene (2), 1β,3β,5β-trihydroxyl-7-isopropenyl-germacren-4(15), 10(14)-diene (3)) were isolated, whose structures were elucidated on the basis of extensive spectroscopic analysis. The absolute configuration of compound 1 was determined by a single crystal X-ray diffraction study using a mirror Cu Kα radiation.     

New triterpene saponins from the root of Ilex pubescens

Two new triterpene glycosides named ilexpublesnin A (1) and ilexpublesnin B (2) were isolated from the root of Ilex pubescens. Their structures were determined as 3-O-(β-d-xylopyranosyl)-28-O-(β-d-glucopyranosyl)-3β, 19α-dihydroxyurs-23-oxo-12-en-28-oic acid (1) and 28-O-(β-d-xylopyranosyl-(2 → 1)-β-d-glucopyranosyl)-3β, 19α-dihydroxyurs-23-oxo-12-en-28-oic acid (2) on the basis of chemical and spectroscopic methods.     

Two new bufadienolides from the rhizomes of Helleborus thibetanus Franch

Two new bufadienolides, named tigencaoside A(1) and tigencaoside B(2), were isolated from the rhizomes of Helleborus thibetanus Franch., along with two known bufadienolides, hellebrigenin (3) and 5β,14β-dihydroxy-19-oxo-3β-[(α-L-rhamnopyranosyl)oxy]bufa-20,22-dienolide (4). Their structures were elucidated on the basis of extensive spectroscopic analysis. Two new compounds were evaluated for their cytotoxic activities against four strains of cultured tumor cells.     

Two new triterpenoids from the roots of Actinidia chinensis

Two new triterpenoids (1, 2), together with one flavonoid glycoside and thirteen known triterpenoids were isolated from the roots of Actinidia chinensis Planch (Actinidiaceae). The structures of the new constituents were elucidated as 12α-chloro-2α, 3β, 13β, 23-tetrahydroxyolean-28-oic acid-13-lactone (1), 2α, 3α, 19α, 23, 24-pentahydroxyurs-12-en-28-oic acid (2). Structure elucidation was accomplished by 1D, 2D NMR spectra (HMQC, HMBC, ¹H-¹H COSY, TOCSY, and NOESY) and mass spectrometry (ESIMS). Moreover, two known triterpenoids showed positive cytotoxic activity against LOVO and HepG2 cell lines.